The Tandy Model 100 is made by Kyocera and sold in Japan as the Kyotronic 85. However, sales weren't very strong and the rights to produce the computer were bought by Tandy.
Since Tandy owned Radio Shack, this machine was sold well. Around 6 million devices sold.
Both Olivetti and NEC sold similar devices, based on the same Kyocera machine. Olivetti the M-10 and NEC the PC-8201 and PC-8300.
The Model 100 can work for 20 hours on 4 AA-batteries. The operating system runs from ROM which is based on Microsoft Basic. Next to the Basic interpreter, there is a terminal program (TELCOM), addressbook (ADDRSS), to-do list (SCHEDL) and a simple text editor (TEXT).